Induction type electricity integrating meter



Aug. 17, 1943. J. PRINCE ETAL 2,325,885

INDUCTION TYPE ELECTRICITY INTEGRATING METERA Filed March 29, 1940 a." g Pimm/dwf l V 7Z` 5 i'f 1 namur/fone il A A um PHY/MAINT Mi/lh' 5 Patented Aug. 17, 1943 Y ii'l? ED STAT ES GFF ICE 2,326,885 INDUCT'IN:TYPE ELECTRICITY INTEGRATING' METEI Johrr andA Maurice. Whitehead, Bollin- WonLEngland, assignors to Fernanti-f Electric rnc., NewYork, N. Y.

Applicall mrchf 29, 1940;v Y Serial No. 326,748 hr Gruft-Britain Mrchf 311,` 1939? This' invention' relatesc tov'induction type electricity integrating meters.

Generally the core of the shunt electromagnet of such meters has to carry a large flux, the bulk of which does no useful work, in order to produce the necessary phase relationship between the shunt driving flux and the applied potential.

An object of the present invention is to provide an induction type electricity integrating meter in which part of the flux set up in the core of a shunt electromagnet is employed for doing useful work other than driving the meter disc.

Another object of the present invention is to provide an improved induction type electricity integrating meter in which part of the ilux set up in the core of a series electromagnet is employed for doing useful work other than driving the meter disc.

Many induction type electricity integrating meters such as two part tarii prepayment meters require an auxiliary source of mechanical power for driving a mechanism such as a xed charge mechanism, and the invention enables such meters to be constructed cheaply, with economy in space and with a symmetrical disposition of Referring to the accompanying diagrammatic K drawing Figure l is a front elevation of a meter embody-` ing the present invention in one form, certain components being omitted for clarity.

Figure 2 is a part sectional side elevation thereof illustrating some of the components omitted from Figure 1.

Figure 3 is a plan view of the meter of Figures 1 and 2.

In carrying the invention into effect according to one form by way of example as illustrated in Figures l to 3 a prepayment induction type electricity meter is adapted for use on a two part tarii system. The meter includes a shunt electrcmagnet the core of which has three separate limbs I, 2 and 3 situated side by side with their parallel to each other in a common plane. The two outer limbs I, 2 each have both ends turned inwards towards the middle limb 3 and the three limbs are held in position relative to each other by two brass strips 4 at each end. A steel back plate 5 is held in contact with the top of the middle limb 3 and passes downwards parallel to the back thereof. At the bottom of the middle limb the back plate 5 is bent at right angles and attached to a so-called tongue piece 6 which projects between the poles of a series electromagnet (C1. ivi- 264i core 24. The shunt electromagnet is'attached to aste'el frame I by means of boltsl 8k which pass through the top and bottom of the two outer limbs I, 2. The limbs are disposed vertically and the middlelimb 3 carries a shunt coil 9. Attached to the tops of the two outer limbs and disposed horizontally is a circular steel plate I0 with a central hole formed therein and teeth projecting radially inwards. The plate I0 is attached to the limbs by means of bolts I2 which pass through holes in ears or anges I I formed integrally with the plate. A second steel plate I3 with teeth projecting radially outwards is disposed within the hole in the plate I0 with the teeth intermeshing but with a small clearance at all parts of the periphery. This second plate I3 is screwed to the top of the back plate. The two plates IU, I3 serve as the stator of a synchronous motor which has for its rotor a permanent magnet in the form of a six-legged spider I4. The spider is carried on a vertical spindle I5 the lower end of which is set in a brass bearing I6 attached to the inner steel plate I3 and the other end of which passes through a hole in a brass bracket I'I attached to the outside stator plate I0. Alternate limbs of the spider are of opposite polarity and at the outer extremity of each limb two teeth are formed which are similar in size to the stator teeth.

The teeth Ha, Mb of alternate pairs are magnetised north and the teeth |40, Idd of the remaining pairs are magnetised south. The teeth Illa, I4b are spaced apart by a distance equal to that between two adjacent teeth on the steel plate I0 while teeth IIIc, Idd are separated by a distance such that when a tooth I4c of each pair is opposite a tooth of the steel plate I3, the other tooth Md of the same pair is opposite to the gap between the next adjacent tooth of the steel plate I3 and the preceding tooth of the plate I0.

The spindle I5 of the synchronous motor has a pinion I8 attached thereto which engages with a toothed wheel and communicates through gearing with one sun wheel I 9 of a differential mechanism and another sun wheel 22 which is connected through gearing 2I to the meter disc 20. The third member 23 of this mechanism communicates the sum of the motions of the other two members I9, 22 to one member of a second vdifferential mechanism (not shown) the other two members of which are connected, also by way of suitable gears, to a switch and a coin mechanism respectively, In other respects the meter is constructed in accordance with known methods.

In operation the shunt and series windings are This condition in conjunction Vwith the specialA arrangementof the rotor poles indicated above ensures that the motor is self-starting and alwaysY runs at synchronousk speed. The gearingbetween j the rotor of the synchronous motor and the irst 1 diierential mechanism is such tl'lattherequire-y ments of the xed charge part of the tariff are met.

The combined shunt and series driving iuXes Y cause the meter disc 20 to rotate when a load is Y imposed on the meter and the amountof electricity used is recorded in known manner.

l. An induction electricity integrating meten including a shunt electromagnet core,` a shunt coil thereon, two shunt magnet limbs separate from said core, an externally toothed stator member in magnetic connection with and symmetrically disposed in relation to said core, an `internally toothed stator member concentrically disposed 'around said first-mentioned stator meinber-'and magnetically connected to said two limbs, a Vrotor,'alternately polarised radial arms on said rotor Vand teeth on said arms co-acting magnetically with the teeth on said stator members.

induction electricity integrating meteras claimed in claim 1,including also a two-limbed series electromagnet core, a back plate of mag- 'netic material, magnetically connected to said "shunt .magnet 'core and a tongue piece of magnetic'material-attached to said back plate and `*projecting between the limbs of said series electromagnet core. Y

' JOHN PRINCE.

MAURICE WHITFIEAD` 

